This invention relates to the tracking of the sun and insolation by means of fiber optics which concentrates light of selected wavelengths onto photovoltaic cells of energy efficient design. Heretofore, a multiplicity of mirrors and/or lenses have been employed in order to focus onto a target which is thereby subjected to intense heat for the generation of energy in one form or another, and all of which requires substantial space and has its limitations with respect to sun tracking. Accordingly, solar energy has been collected through the insolation of heat via a fluid media into a storage mass and through the generation of electrical energy by photovoltaic means, it being a general object of this invention to provide improved concentration by means of fiber optics, whereby sunlight is concentrated and divided according to wavelength and directed onto photovoltaic cells that are complementary to said wavelengths and therefore energy efficient.
Filaments of certain transparent materials are known to transmit light over considerable distances and at reasonably high efficiency. Silica glass and certain plastic filaments are reasonably inexpensive materials used for this purpose, and quartz filaments are more expensive and known for high intensity concentration and/or transmission of light. Fiber optics utilizing bundles of elongated filaments for the transmission of light are known to transmit light efficiently, with internal reflection defined by an accepted reception and internal reflection angle of 68.degree.. The great advantage in these bundles of fibers is their flexibility and the angular redirection of light made possible thereby. It is an object of this invention to advantageously employ the angular redirection of light available with fiber optic bundles for the concentration of sunlight into or onto energy generator means, such as photovoltaic cells. In practice, sun tracking is by means of an astro-clock that maintains a primary concentrator in normal alignment with the suns rays, or a fixed primary concentrator with special lenses and/or reflectors. With the present invention, primary concentration directs a multi-sun band of light through a prism that separates it into a spectrum of monochromatic bands ranging from infrared to ultraviolet, and to each of said spectrum bands at least one bundle of fiber optic filaments is exposed and directed to a complementary photovoltaic cell that operates efficiently within the range of light to which it is exposed.
The heat of solar concentration is diverted in the protective system provided herein so that plastic or silica glass or quartz fibers may be used as required. Although high temperature quartz fiber optic filaments are readily available, their cost is greater than that of the other mentioned fibers. Accordingly, it is an object of this invention to transmit cold light concentration where the source ends of the fiber optic filaments must be protected from excessive heat otherwise caused by the concentration of intensified light. In practice, the insolation of heat by transmission through the prism is by means of a heat storage media, a fluid, that is circulated therethrough.
The angular redirection of sunlight and its concentration onto the generating plane of the photovoltaic cell or cells is by means of training the bundles of fiber optic filaments from a spectrum plane to an energy generating plane, or planes. Accordingly, the entire source area or plane is arranged selectively according to light wavelength, and the bundles of light pipes are selectively directed onto a plurality of photovoltaic cells that are subjected to all of the light emanating through the prism, for complete and efficient energy generation.